The present invention relates to a method and apparatus for producing hermetic, hard-sealed plasma tubes for gas laser applications, and to a novel plasma tube product the mirror mountings of which can be adjusted after assembly and baking. More particularly, the invention relates to a technique for producing such hard-seal plasma tubes by a baking process which can be carried out in a single step or small number of steps to produce a hard-sealed plasma tube. As used herein, the term "hard-sealed" will refer to hermetic, high temperature vacuum tight seals such as glass-to-metal seals, ceramic-to-metal seals, and brazed metal seals utilizable in the present invention.
The referenced application discloses a technique for manufacturing laser plasma tubes in which various combinations of matching metals and glasses are provided so that it is possible by a multiple step process to make up a laser plasma tube having hard seals or optionally having epoxy seals for attaching the end mirrors in place. It is highly desirable to construct laser plasma tubes in which all seals are glass-to-metal thereby permitting high temperature vacuum processing and also eliminating problems caused by the permeability of epoxy type seals to water vapor; which although quite low, limits laser plamsa tube life. However, the previously used techniques, such as are shown in the referenced Crane et al. application, required multistep flame processing and considerable skilled labor. There is, therefore, a need for a new and improved method and apparatus for producing a hard-sealed laser plasma tube.